JPS5746691A - Torque controller for thyristor motor - Google Patents

Abstract

PURPOSE:To suppress the torque ripple of a thyristor motor, by a method wherein the motor current is varied according to the difference between the momentary torque obtained from both a current command signal and a position signal and the average torque obtained from both the current command signal and a firing phase command signal. CONSTITUTION:According to the output signal from an automatic pulse phase shifter 12, the output current waveform of a cycloconverter 1 is calculated and fed to a d.q converting circuit 15 as two-phase signals ialpha, ibeta, together with the position signal from a position detector 11, where the d axis and q axis components of current are calculated according to a current command signal Iap. In a momentary torque calculating circuit 16, a momentary torque taue and such an advance angle betao that the torque ripple minimizes under said operating condition are calculated from id, iq and a field current command Ifp. On the other hand, in an average torque calculating circuit 17, an average torque -taue is calculated from the current command signal Iap, the field current command Ifp and the advance angle betao. The torque deviation DELTAtaue between taue and -taue is differentiated in a differentiating circuit 7 and fed to a current amplifier 9.